Albert m



Reissuecl Sept. 20, s 1932 UNITED STATES PATENT OFFICE ALBERT m.cnrr'ronn, or'sfrow, onro, nssrenon T 'rnsooomzmn TIRE & RUBBER.

COMPANY, OF AKRON, O HIO,:.A CORPORATION OF OHIO RUBBER 'CbMPOUND METHODOF PRESERVING IT ,No Drawing. Original No. 1,823,531, dated September15, 1931, Serial No. 216,780, filed August 31, 1927; Application forreissue filed June 9, 1932. Serial No. 616,357.

My invention relates to the treatment of rubber and has for its primaryobjectthe provision of a material which is adapted to be incorporated inrubber for the purpose of retarding the deterioration thereof;

One of the chief objects of the invention is to provide an antioxidantfor rubber composed of the reaction product of a diamine and anaphthalene compound such as a naph thol.

By the incorporation of certain amino bodies in a rubber compound, thephysical and chemical characteristics of the latter are materiallyaffected. Certain of these compounds are employed as accelerators of therate of vulcanization of rubber. Another group, when introduced intorubber, causes a reduction of oxidation or ageing of the rubber, thusgreatly prolonging the period pf usefulness of articlesmanu'facturedthererom.

I have made the discovery that naphthyl substituted diamines may beemployed in a rubber compound as antioxidants. These 'materials may beprepared by the reaction of the naphthols, either alpha or beta, on adiamine. Theoretically, the general reaction of these substances isrepresented as follows:

In the above equation Rrepresents a hydrocarbon residue, either aryl oralkyl, and R and R represent hydrogen atoms or substitutes therefor. I

' Illustrative of compounds falling within "the scope of my inventionxisthe reaction one-halfmol of anhydrous calciumchloride. These materialsare then heated in a closed vessel for a period of from five to eighthours at a temperature of approximately 270 degrees C. lVhen'thereaction is complete, a yellow, reaction product separates out asa layeruponthe top of the other materials. This reaction product is separatedfrom the other materials and purified by washing, first with water, thenwith dilute acid, and finally with dilute ammonia. ,The washed materialis then dried and may be obtained as a crystalline product bycrystallization from either alcohol or xylene. The melting point of thecrystalline material ranges from 146 to 148 degrees C. The crystallinenature of this material and the fact that it has a very definitemelting. point, are strongly indicative that, it is a true chem icalreaction product, the chemical equation for which is represented asfollows:

I l o' NcmcmN The above method is not limited to the specific materialsindicated, but is of general application in the preparation of allmaterials of this class. I

My invention is not limited to the reaction productsof alkylene diaminesand naphthols, but also includes the reaction products of resin-likesubstance is believed to consist of The material thus obtained istworeaction products (symmetrical dibeta naphthyl meta phenylene diamineand unsymmetrical mono beta naphthyl meta phenylene dial nine). Thereactions between the amino body and the naphthol may be represented bythe following equations:

The materials prepared ac'cording'to the above processes may beincorporated in most of the standard rubber compounds c0ntain ingvarious proportions'of the compounding ingredients. The following: is anexample of a formula which has been found to give excellent results: 7

. Parts by p weight Acetone extracted pale creperubber 100 Zinc oxide; 5Sulfur"; V 3 Stearic acid '1. 5 Hexamethylene tetramine 1 Antioxidant 1Tests conducted upon samples prepared in accordance with the formulaclearly show the value of the materials as antioxidants. a

The data obtained from the tests is contained in the following tables,Tables I and II containing the data obtained from samples which had notbeen subjected to artificial ageing.

A TAB E I Sym. d'i (beta naphthylamino) ethane Cure I 500% 700% TensilePercent 77 along. along. strength elong. Timem Lbsper kgs/cm kgs/cmkgs/em' atbreak mms. sq. in.

TABLE II M-pheny lene 'diamine derivative of beta naphtha! so 40 15 86s20 50 40 1 24 78 132 e00 70 40 106 160 770 Samples were also tested toascertain their age-resisting properties .by subjecting them to atemperature of 50 degrees C. and a pressure of 150 pounds per squareinch in an thereby.

oxygen bomb for six days. The results obtained are indicated in tablesIII and IV appended hereto. It will be observed that the tensilestrength in most cases is materially improved after subjection to theartificial ageing, a and thatv but a slight increase in Q OE .c

weight, due to the absorption of oxygen, is observed.

TABLE III v Sym. dt'flieta naphthyla/mtno) ethane Cure I Percent 7 ."MQ/7007 Tenslle chug. elong strength g g Tune in Lbs. per kgs/cm kgslcmkgslcm break 7 1111115., sq. m.

a0 40 23 71 117 800 o. 10 50 40 34 118 167 765 0.12 7Q 43 152 188 7400.28

i TABLE IV M -phenylene date/mine derivative of betanaphthot 30 40 20 65116 815 0. 0 50 40 30 102 173 800 0. 0O 7 70 I 4 0 L 38 137 176 750 0.32

The chemical formulas which have been given in explanation of thereactions which take place, during the process of preparation of theantioxidants, are believed tobe in accordance with the generallyacceptedtheories. However, the usefulness of my invention is 7 not dependentupon the "correctness of the latter, and consequently the validity ofany patents obtained should not be affected Although I have disclosedonly I the preferred embodiments of my invention and decomprisesincorporating a substance having the chemical formula r r a @avomonmfl)into a rubber compound and vulcanizing the mixture.

2. A method of' preserving rubber which comprises incorporatingdinaphthyl ethylene diamine into .-a rubber compound and vulcanizing themixture.

3. A rubber product which has been vulcanized in the presence of thereaction prod- 7 not of a naphthol and ethylene diamine.

4. A rubber product which has been vulcanized in the presenceofdinaphthyl ethylene diamine.

5. A method of preserving rubber which comprises incorporating therein areaction product of a naphthol with a diamineselected from a groupconsisting'of ethylene diamine and phenylene diamine.

6. A method of preserving rubber which comprises incorporating therein.a material having the following formula:

H H Rl l'R1N -R2,

in which R and R are naphthalene groups,

and R is a group selected from a group consisting of benzene andethylene.

7. A rubber product that has been vulcanized in the presence of amaterial having the formula:

in which R and R are naphthalene groups and R is a radical selected froma group consisting of ethylene and phenylene.

In witness whereof I have hereunto signed my name.

Signed at Akron, in the county of Summit and State of Ohio, U. S. A.,this 3d day of June, 1932.

ALBERT M. CLIFFORD.

